Provided is a single inductor multiple output (SIMO) direct current-to-direct current (DC/DC) converter that may perform DC/DC conversion by transferring, to output nodes, input current that is input and thereby stored in a single inductor. An output selection unit of the SIMO DC/DC converter may select, from output nodes, a first output node to be supplied with current from a driving unit, and provide output voltage of the first output node and reference voltage of the first output node to a hysteresis comparison unit. The hysteresis comparison unit may control on-time and/or inductor peak current by determining whether the output voltage of the first output node is higher than the reference voltage of the first output node by at least a first threshold, and whether the output voltage of the first output voltage is lower than the reference voltage of the first output voltage by at least a second threshold.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A converter, comprising: an output selection unit to select, from a plurality of output nodes, a first output node to be supplied with current from a driving unit; a comparison unit to determine whether an output voltage of the first output node is higher than a reference voltage of the first output node by comparing the output voltage of the first output node with the reference voltage of the first output node; and a control unit to adjust a first time length to be a maximum time length in which the current is continuously supplied to the first output node based on the determination result, wherein the control unit comprises: an on-time controller to increase the first time length when a counted number of current supplies exceeds a maximum number of current supplies; and an inductor peak current controller to control a peak value of input current.
2. The converter of claim 1 , wherein the comparison unit is a hysteresis comparison unit to determine whether the output voltage of the first output node is higher than the reference voltage of the first output node by at least a first threshold, and to determine whether the output voltage of the first output voltage is lower than the reference voltage of the first output voltage by at least a second threshold.
3. The converter of claim 2 , wherein the comparison unit comprises: a first RS flip-flop corresponding to the first output node; a first comparator to compare the output voltage of the first output node with a voltage higher than the reference voltage of the first output node by the first threshold; a second comparator to compare the output voltage of the first output node with a voltage lower than the reference voltage of the first output voltage by the second threshold; and at least one multiplexer to transfer an output value of the first comparator and an output value of the second comparator to the first RS flip-flop, and the first RS flip-flop stores the output value of the first comparator and the output value of the second comparator.
4. The converter of claim 3 , wherein the first RS flip-flop transfers the output value of the first comparator and the output value of the second comparator to the control unit to count the number of current supplies to which current is supplied by the control unit to the first output node until the output value of the first comparator becomes to be higher than the reference voltage of the first output node by the first threshold after the output voltage of the first output node is lower than the reference voltage of the first output node by at least the second threshold.
5. The converter of claim 3 , wherein the control unit comprises: a counter to count the number of current supplies to which current is supplied by the control unit to the first output node until the output value of the first comparator becomes to be higher than the reference voltage of the first output node by the first threshold after the output voltage of the first output node is lower than the reference voltage of the first output node by at least the second threshold; and a number of rising (NR) comparator to compare the counted number of current supplies with a predetermined maximum number of current supplies.
6. The converter of claim 5 , wherein: when the first time length exceeds a first maximum time length set with respect to the first output node by increasing the first time length, the on-time controller provides an instruction signal instructing to increase a peak value of input current that is input to the driving unit, without increasing the first time length, wherein the inductor peak current controller controls the peak value of input current to increase by transferring the instruction signal to the driving unit.
7. The converter of claim 5 , wherein: the NR comparator compares the counted number of current supplies with a predetermined minimum number of current supplies, and the on-time controller is set to decrease the first time length when the counted number of current supplies is less than the minimum number of current supplies.
8. The converter of claim 7 , wherein: when the first time length becomes to be less than a first minimum time length set with respect to the first output node by decreasing the first time length, the on-time controller provides an instruction signal instructing to decrease a peak value of input current that is input to the driving unit, without decreasing the first time length, and wherein the inductor peak current controller controls the peak value of input current to decrease by transferring the instruction signal to the driving unit.
9. A single inductor multiple output (SIMO) direct current-to-direct current (DC/DC) converter, comprising: a driving unit to store input current that is received from a single input node during a charging time duration and to transfer the stored input current to a plurality of output nodes during a discharging time duration; a load switch controller to supply current to a first output node among the plurality of output nodes during a first time length corresponding to the first output node within the discharging time duration, wherein the current is transferred by the driving unit; a comparison unit to compare an output voltage of the first output node with a reference voltage corresponding to the first output node; an on-time controller to increase the first time length when a counted number of current supplies exceeds a maximum number of current supplies; and an inductor peak current controller to control the peak value of input current.
10. The SIMO DC/DC converter of claim 9 , wherein the SIMO DC/DC converter is a hysteresis comparison unit to determine whether the output voltage of the first output node is higher than the reference voltage of the first output node by at least a first threshold, and to determine whether the output voltage of the first output voltage is lower than the reference voltage of the first output voltage by at least a second threshold.
11. The SIMO DC/DC converter of claim 9 , wherein the controller comprises: a counter to count the number of current supplies to which current is supplied by the controller to the first output node until an output value of a first comparator becomes to be higher than the reference voltage of the first output node by a first threshold after the output voltage of the first output node is lower than the reference voltage of the first output node by at least a second threshold; a number of rising (NR) comparator to compare the counted number of current supplies with a predetermined maximum number of current supplies or a predetermined minimum number of current supplies; and the on-time controller decreases the first time length when the counted number of current supplies is less than the minimum number of current supplies.
12. The SIMO DC/DC converter of claim 11 , wherein when the first time length exceeds a first maximum time length set with respect to the first output node by increasing the first time length when the counted number of current supplies exceeds the maximum number of current supplies, the on-time controller provides an instruction signal instructing to increase a peak value of input current that is input to the driving unit without increasing the first time length, the inductor peak current controller controls the peak value of input current to increase by transferring the instruction signal to the driving unit.
13. The SIMO DC/DC converter of claim 11 , wherein when the first time length becomes to be less than a first minimum time length set with respect to the first output node by decreasing the first time length when the counted number of current supplies is less than the minimum number of current supplies, the on-time controller provides an instruction signal instructing to decrease a peak value of input current that is input to the driving unit without decreasing the first time length, and the inductor peak current controller controls the peak value of input current to decrease by transferring the instruction signal to the driving unit.
14. A method of controlling a converter, the method comprising: selecting, by an output selection unit from a plurality of output nodes, a first output node to be supplied with current from a driving unit to provide an output voltage of the first output node and a reference voltage of the first output node to a hysteresis comparison unit; determining, by the hysteresis comparison unit, whether the output voltage of the first output node is higher than the reference voltage of the first output node by at least a first threshold, and whether the output voltage of the first output voltage is lower than the reference voltage of the first output voltage by at least a second threshold; counting, by a control unit, the number of current supplies to which current is supplied by the control unit to the first output node until a output value of a first comparator becomes to be higher than the reference voltage of the first output node by the first threshold after the output voltage of the first output node is lower than the reference voltage of the first output node by at least the second threshold; adjusting, by the control unit the first time length in accordance with the counted number of current supplies; and providing, by the control unit, an instruction signal instructing to modify a peak value of input current that is input to the driving unit without modifying the first time length.
15. The method of claim 14 , further comprising: comparing, by the control unit, the number of current supplies with a predetermined maximum number of current supplies or a predetermined minimum number of current supplies; and increasing, by the control unit, the first time length when the counted number of current supplies exceeds the maximum number of current supplies, and decreasing the first time length when the counted number of current supplies is less than the minimum number of current supplies.
16. The method of claim 15 , further comprising: providing, by the control unit, an instruction signal instructing to increase a peak value of input current that is input to the driving unit without increasing the first time length, and, when the first time length exceeds a first maximum time length set with respect to the first output node by increasing the first time length when the counted number of current supplies exceeds the maximum number of current supplies.
17. The method of claim 15 , further comprising: providing, by the control unit, an instruction signal instructing to decrease a peak value of input current that is input to the driving unit without decreasing the first time length, when the first time length becomes to be less than a first minimum time length set with respect to the first output node by decreasing the first time length when the counted number of current supplies is less than the minimum number of current supplies.
18. A non-transitory computer-readable recording medium storing a program to implement the method of claim 14 .
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June 13, 2012
April 14, 2015
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